Well, from a relative newbie that's discovered issues in dates that were not displaying correctly -- I would think the problem is not in the Value List but in the field displaying the results.
You might go the field displaying the results in Edit Layout mode and then look in the Format toolbar under Time. I think it sets options there for how the time is to be displayed, and somehow you've now got it set to display seconds.
Thanx for the suggestion but sadly that's not it. The format options only change the data once it's been selected from the value list.
My problem is that the actual value list is displaying with seconds, whereas the value list itself only has hours and minutes in it! And for the life of me I can't work out why! A friend has been looking over my file but he also can't see the error.
Any other suggestions, anyone?